Patenting steel



ALIEN PROPERTY CUSTODIAN PATENTING STEEL Elmer E. Lcgge, West Hartford, Conn.

No Drawing. Application May 4. 1942, Serial No. 441,678

3 Claims. (Cl. 148-21) This invention is concerned with patenting steel by means of a liquid patenting quench bath, the object being to produce a more uniformly patented structure than has heretofore been possible.

conventionally, the steel, usually in the form of rod or wire, is continuously moved through an austenitizing heating zone, provided by either a continuous furnace or a high temperatured lead bath, and is then continuously moved through the liquid patenti n uench bath, wh may be either a mol'ten safi' Wag steel am enter the patenting quench ba while it is still austenitic from its passage through the austenitizing heating zone, which means that when the steel enters it is at a much higher temperature than that of the patenting quench bath. Furthermore, the steel necessarily enters the patenting quench bath continuously at the same location. and travels therethrough in the same path during its patenting, this producing a high temperature zone in the patenting quench bath surrounding the steel's entering location and which decreases gradually in temperature to indeterm-inable distances thereheyond, where it becomes merged with the patenting quench bath.

As a result of the above practice. the steels austenite transforms, as the steel passes through the patenting quench bath, at widely varying temperatures imparting a mixed structure to the steel ranging from very coarse pearlite to relatively fine pearlite, or sorbite, it being understood that patenting is carried out in the temperature range where austenite very rapidly transforms to pearlite, namely, within the temperature range of from 800 to 1350 F. It is most desirable to produce a uniform structure consisting throughout of the austenite transformation product inherent to the specific patenting temperature at which the patenting quench bath is maintained. it being otherwise. impossible to accurately predict the properties of the patented steel.

According to the present invention, the foregoing practice is improved by continuously moving the austenitlzed steel leaving the auslenitizing heating zone and prior to its enteringthe patenting quench bath, a li d ench bat having a subs ti 7 lower temper-a517 e E an the patenting uench bath with suitable length reducing the temperature of the steel at least approximately to that of the patenting quench in a time period too short to permit morethan minor amounts of the steel's austenite to transform, whereby the steel enters the patenting quench in at least a mainly austenitic condition at a temperature not substantially higher than that of this quench and thus avoids the formation therein of a high temperature. zone.

This liquid prequench bath-may consist of any suitable quenching liquid, it functioning to rapidly abstract the heat imparted to the steel as it moved through the austenit heating z'one, preferably without permitting any austenite transformation, the steel then entering the patenting quench bath at almost the same temperature of this bath, or even at a slightly lower temperature. The formation of a widely varying temperature zone in the prequenoh bath is immaterial since there is little or no austenite transformation effected therein, it functioning merely to abstract heat from the steel. A high temperature zone cannot occur in the patenting quench bath. Should a low temperature zone occur in the entering end of the patentingquench bath, any austenite transformation occurring in this zone will produce a structure that will automatically be tempered as the remainder of the austenite goes to the patented structure, and will result in a tempered product having substantially the same physical properties as this patented structure.

The temperature of the prequenchlng bath should preferably range from 350 to 700' 1"., while patenting temperatures are herein consi ered as ranging from 800' to 1350 E, this last range applying to the-patenting quench bath. This patenting range is advanced since it represents the temperature range where austenite very rapidly transforms to peat-lite, and, therefore, involves the problem solved by this invention:

very fine pearllte, or sorbite, being producedthe lower limits of the range, and very coarse 'pearlite being produced at the upper limits of the range. The exact temperature of the prequenching bath will depend on its length and the steel. it being preferable to a'tenting quench bath atsubstantially the the latter, but any prequenching is for other purposes not con-- nected with the problem solved by the present invention. this accounting for the reason that the prequenching disclosed herein has been unobvious to those skilled-in the art in connection with patenting.

I claimr 1. In the art 01 patenting steel by continuously proving it successively through an austenitizing heating zone anda liquid :patenting quench maintained at a temperature within the range causing rapid transformation of austenite to pearlite, the improvement comprising continuously moving the austenitized steel leaving said zone and prior to its entering said quench,

' through a liquid prequench having a temperature and length reducing the temperature of the steel at least approximately to that or the pattentlng quench in a time period too short to permit more than minor amounts or the steels austenite to transform, whereby the steel enters the patenting quench at a temperature not substantially higher than that of this quench and of the patenting quench.

avoids the formation therein oi a higher temperature zone.

2. A method or patenting steel, comprising continuously moving the steel through a heating zone rendering the steel austenitic. moving the austcnitic steel through a liquid prequench maintained at a temperature within the range oi from 350 to 700 F. for a time sumclent to reduce the steel'stemperature substantially to within the, range of from 800 to 1350 R, and. prior to more than minor amounts of the steels austenite transforming, moving the steel through a liquid patenting quench maintained throughout at a temperature within the range or from 800' to 1350' F.

3. A method of patenting steel, comprising continuously moving the steel through a heating zone rendering the steel austenitic, moving the austenitic steel through a. liquid prequench maintained at a temperature within the range of from 350' to 700 F. for a time sufficient to reduce the steel's temperature substantially to within the range oi from 800 to 1350 F., and prior to more than minor amounts of the steel's austenite transforming, moving the steel through a liquid patenting quench maintained throughout at a temperature within the range of from 800' to 1850 FL, said prequench time being 's'uiiieient to reduce the steel's temperature at least to that mama E. LEGGE.

CERTIFICATE OF C ORBECII ON Patent No. 2,52h,650.

ELHER E. LEGGE.

July 19h;-

It is hereby certified that error appears in the above numbered patent requiring correction as follows the top thereof, strike out the Page 101 the printed specification, near words sert instead -UNI'I'ED STATES PATENT OFFICE--;

"ALIEN PROPERTY CIUSTODIAN' and inand that the said Letters Patent should be read with this correction therein.

Signed and. sealed this 21st day of September,

(Seal) Henry Van Arsdale Acting Commissioner of Patents.

prequenching is for other purposes not con-- nected with the problem solved by the present invention. this accounting for the reason that the prequenching disclosed herein has been unobvious to those skilled-in the art in connection with patenting.

I claimr 1. In the art 01 patenting steel by continuously proving it successively through an austenitizing heating zone anda liquid :patenting quench maintained at a temperature within the range causing rapid transformation of austenite to pearlite, the improvement comprising continuously moving the austenitized steel leaving said zone and prior to its entering said quench,

' through a liquid prequench having a temperature and length reducing the temperature of the steel at least approximately to that or the pattentlng quench in a time period too short to permit more than minor amounts or the steels austenite to transform, whereby the steel enters the patenting quench at a temperature not substantially higher than that of this quench and of the patenting quench.

avoids the formation therein oi a higher temperature zone.

2. A method or patenting steel, comprising continuously moving the steel through a heating zone rendering the steel austenitic. moving the austcnitic steel through a liquid prequench maintained at a temperature within the range oi from 350 to 700 F. for a time sumclent to reduce the steel'stemperature substantially to within the, range of from 800 to 1350 R, and. prior to more than minor amounts of the steels austenite transforming, moving the steel through a liquid patenting quench maintained throughout at a temperature within the range or from 800' to 1350' F.

3. A method of patenting steel, comprising continuously moving the steel through a heating zone rendering the steel austenitic, moving the austenitic steel through a. liquid prequench maintained at a temperature within the range of from 350' to 700 F. for a time sufficient to reduce the steel's temperature substantially to within the range oi from 800 to 1350 F., and prior to more than minor amounts of the steel's austenite transforming, moving the steel through a liquid patenting quench maintained throughout at a temperature within the range of from 800' to 1850 FL, said prequench time being 's'uiiieient to reduce the steel's temperature at least to that mama E. LEGGE.

CERTIFICATE OF C ORBECII ON Patent No. 2,52h,650.

ELHER E. LEGGE.

July 19h;-

It is hereby certified that error appears in the above numbered patent requiring correction as follows the top thereof, strike out the Page 101 the printed specification, near words sert instead -UNI'I'ED STATES PATENT OFFICE--;

"ALIEN PROPERTY CIUSTODIAN' and inand that the said Letters Patent should be read with this correction therein.

Signed and. sealed this 21st day of September,

(Seal) Henry Van Arsdale Acting Commissioner of Patents. 

